KR20030087533A - Asymmetric porting for multi-rotor screw compressor - Google Patents

Abstract

The multi-rotor screw compressors each form three or more parallel rotor housing sections that house the rotor, and adjacent rotors form two or more compressor pairs and include suction and discharge ports for each of the compressor pairs and a first closure. A compressor housing further comprising at least two auxiliary ports selected from the group consisting of a lobe port, a final closed lobe port, and a equalization port, wherein at least one of the auxiliary ports communicates with a first pair of two or more pairs, The port communicates with a second pair of two or more pairs, thereby reducing interference between auxiliary ports. According to another aspect of the invention, the first compressor pair communicates with the equalization port and has a first discharge port, the second compressor pair has a second discharge port without communicating with the equalization port, and the first discharge port and the second discharge port. the discharge port is selectively determined by the dimensions so as to provide a second exhaust ratio (V _i) a lower index than the volume port to the discharge port. According to another aspect of the invention, the first compressor pair communicates with the equalization port and has a first discharge port, the second compressor pair has a second discharge port without communicating with the equalization port, and the first discharge port and the second discharge port. the discharge port is selectively determined by the dimensions so as to provide a second exhaust ratio (V _i) a lower index than the volume port to the discharge port.

Description

Asymmetric porting for multi-rotor screw compressors {ASYMMETRIC PORTING FOR MULTI-ROTOR SCREW COMPRESSOR}

The present invention relates to a multi-rotor screw compressor, and more particularly to an improved porting configuration for such a compressor.

Twin-rotor screw compressors are known and generally relate to a compressor having a housing that forms a rotating chamber for two rotors, which usually have a number of different ports. The main ports are the suction and discharge ports, and the auxiliary ports usually used in screw compressors are the first hermetic lobe (FCL) port, the final hermetic lobe (LCL) port, the economizer port and other pressure balancing ports. . Each of these ports performs different system functions with respect to compressor operation.

Multiple rotor screw compressors are known and have a housing that forms two or more rotor chambers with three or more rotors that form two or more parallel pairs, each of which can operate as a separate compressor pair. Providing the various ports described above for such compressors can cause problems because the various ports may interact with each other depending on the compressor structural details and system operating conditions. Such interaction can substantially impede the efficient operation of the compressor.

Based on the foregoing, there remains a need for an improved housing and potting structure for multiple rotor screw compressors.

It is therefore a primary object of the present invention to provide an improved housing and potting structure for such a compressor so that the compressor can operate more efficiently.

Another object of the present invention is to provide a potting for a multi-rotor screw compressor that reduces operating noise.

Other objects and advantages of the present invention will appear below.

1 shows a trapped volume with suction, discharge and equalization port regions for the upper female thread of a multiple rotor screw compressor as a function of male beta angle.

FIG. 2 shows a trapped volume with suction port area, LCL port area, FCL area port and discharge port area for the lower female thread of a multi-rotor screw compressor as a male beta angle function.

Figure 3 shows schematically the positioning of the housing part of a multi-rotor screw compressor and the equalization and discharge ports thereon.

<Description of Symbols for Main Parts of Drawings>

10: housing

12, 14, 16: housing section

18: equalization port

20, 22: discharge port

According to the present invention, the foregoing objects and advantages are easily achieved.

According to the invention, there are formed three or more parallel rotor housing sections each containing a rotor, adjacent rotors forming two or more compressor pairs, comprising inlet and outlet ports for each of the compressor pairs; A compressor housing further comprising at least two auxiliary ports selected from the group consisting of one closed lobe port, a final closed lobe port and a equalization port, at least one of the auxiliary ports communicating with a first pair of two or more pairs, The remaining auxiliary port is provided with a multi-rotor screw compressor in which interference between the auxiliary ports is reduced by communicating with a second pair of two or more pairs.

Also in accordance with the present invention, equalization ports are provided only in a single pair of multiple pairs of screw compressors, and discharge ports for multiple pairs are selectively dimensioned to provide a lower volumetric index ratio to the equalized pairs than unbalanced pairs. . This provides for efficient compressor operation and also helps to reduce noise due to pressure pulsations and the like.

Asymmetrical distribution of the ports according to the invention can be advantageously used to provide efficient operation of multiple rotor screw compressors while avoiding interference between the ports to improve overall performance.

The detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings follows.

The present invention relates to a multi-rotor screw compressor, and more particularly to the construction of a housing and potting structure for a multi-rotor screw compressor for improving the operating efficiency and reducing the operating noise of the compressor.

As described above, screw compressors usually have suction and discharge ports for inlet and outlet of fluid, and include a pressure equalizing port, a final hermetic lobe (LCL) port, a first hermetic lobe (FCL) port, a pressure balancing port, and the like. It further comprises an auxiliary port of various forms. In conventional dual rotor compressors, these ports have been positioned in various positions in communication with the screw pair to improve the operation of the compressor.

In multi-rotor screw compressors, ie screw compressors with two or more rotors, improved operation is achieved by positioning the auxiliary port asymmetrically between multiple pairs of adjacent and parallel rotors and / or configuring the port structure. It has been appreciated that such porting location setting and its configuration may be configured to avoid undesirable communication between ports. This structure can also be configured to optimize the volumetric index ratio (V _i ) for the male and female compressor pockets for each pair and pair to improve the efficiency of the compressor, reduce noise and provide an overall reliable device. .

According to the invention, each pair should have a suction port and a discharge port, but the remaining ports of the multi-rotor screw compressors are preferably positioned to position these ports in a position that works efficiently to provide the desired results without interfering with each other. It can be preferably separated between pairs.

1 and 2 diagrammatically show port regions and trapped volumes for a female compressor of a multi-rotor screw compressor such as partially shown in FIG. 3.

1 corresponds to the configuration of the first pair formed by the first female rotor and the male rotor, and FIG. 2 corresponds to the second pair formed by the second female rotor and the male rotor.

Figure 1 shows that the first pair includes suction ports and discharge ports, and shows port regions therefor, and also includes equalization ports positioned therebetween and communicating with these pairs at positions along the male beta or crank angles. Illustrated.

Figure 2 shows a second pair, which pair has a suction port and a discharge port as shown by the corresponding suction port and discharge port regions of Figure 2, and the final hermetic lobe LCL as schematically shown. And a port and a first hermetic lobe (FCL) port. This pair is not in direct communication with the uniform port of the first pair. 1 and 2, the first pair is provided with suction and discharge ports, the second pair is also provided with suction and discharge ports, and an auxiliary comprising a pressure equalizing port, a final hermetic lobe port and a first hermetic lobe port. The port area or trapped volume for a three rotor screw compressor in which the ports are distributed asymmetrically between the two pairs is shown. In this way, as desired in accordance with the present invention, equalization ports can be provided for improved operation of the first pair without interference or communication with the second hermetic lobe and the first hermetic lobe port.

1 and 2 also schematically show an asymmetrical configuration of the discharge port region for the first and second pairs. FIG. 1 shows the discharge port area larger than that of FIG. 2 and the discharge port opening faster than that of FIG. This results in a volumetric exponent ratio for the pair of FIG. 1 lower than the pair of FIG. 2 and, according to the present invention, is preferred since FIG.

Figure 3 also illustrates this aspect of the invention and shows a housing 10 of a multi-rotor screw compressor that forms three parallel rotor housing sections 12, 14, 16, each containing a rotor (not shown). . Usually, the housing sections 12 and 16 rotatably receive the negative rotor, respectively, and the housing section 14 houses the male rotor. Adjacent rotors functionally combine with each other to form a compressor pair. Thus, in the embodiment of Figure 3, the rotors in the housing sections 12, 14 form a first compressor pair, and the rotors in the housing sections 14, 16 form a second compressor pair. FIG. 3 shows a first pair with a equalization port 18 that functions to inject fluid at midrange pressures as opposed to a compression cycle. Figure 3 also shows discharge ports 20, 22 incorporating each pair of compressors. As shown schematically in FIGS. 1 and 2, a multi-rotor screw compressor according to the present invention has a larger discharge port 22 in a pair comprising a equalization port 18 and does not include a equalization port 18. It has a smaller discharge port 20 compared to the discharge port 22 in the non-pair. As mentioned above, this preferably functions to eliminate overcompression of the equalized pair, thereby reducing the discharge noise and pressure pulsations that may otherwise occur. In this way, each pair can be independently optimized with the same operating conditions, and each can be selected to meet the desired output of the compressor.

Each type of configuration of the housing and potting structure of the multi-rotor compressor described above is individually designed to optimize the operating efficiency of the screw compressor, the balance (V _i ) conditions at various locations of the compressor and to avoid interference or communication between the various ports. Or in combination. The end result is a more efficient compressor that runs quieter and is less likely to operate under conditions where compressor damage may occur.

Although the present specification describes a three rotor compressor for the case of two female rotors and a single male rotor, other multiple rotor configurations are possible, and the teachings of the present invention may be readily applied to the same.

The present invention is not limited to the contents shown and described herein, but is merely considered as an example of an optimal mode for carrying out the invention, and variations in the form, dimensions, arrangement and details of operation of the parts are possible. The present invention includes all such modifications within the spirit and scope as defined by the claims.

The present invention provides a multi-rotor screw compressor in which the compressor can operate more efficiently by providing an improved housing and potting structure for the compressor.

Claims (5)

Each forming three or more parallel rotor housing sections containing a rotor, adjacent rotors forming two or more compressor pairs, each comprising a suction and discharge port, a first closed lobe port And a compressor housing further comprising at least two auxiliary ports selected from the group consisting of a final closed lobe port and a equalization port, at least one of said auxiliary ports communicating with a first pair of said at least two pairs, And the auxiliary port communicates with a second pair of the two or more pairs, thereby reducing interference between the auxiliary ports. The method of claim 1, wherein the first pair is in communication with the equalization port and has a first outlet port, and the second pair has a second outlet port without communicating with the equalization port, wherein the first outlet port and the And a second discharge port is selectively dimensioned to provide the first discharge port with a lower volumetric index ratio (V _i ) than the second discharge port. Each forming three or more parallel rotor housing sections containing a rotor, adjacent rotors forming two or more compressor pairs, each comprising a suction and discharge port, a first closed lobe port And a compressor housing further comprising at least two auxiliary ports selected from the group consisting of a final closed lobe port and a equalization port, wherein at least two said auxiliary ports are distributed asymmetrically between said pair of compressors. Screw compressor. 4. The compressor of claim 3, wherein a first pair of compressor pairs is in communication with the equalization port and has a first outlet port, and a second pair of compressor pairs has a second outlet port without communicating with the equalization port; The first and second outlet ports are selectively dimensioned to provide the first outlet port with a lower volumetric index ratio (V _i ) than the second outlet port. A compressor housing, each forming three or more parallel rotor housing sections containing a rotor, wherein adjacent rotors form two or more compressor pairs, wherein a first pair of the two or more compressor pairs is in communication with the equalization port; And a first outlet port, a second pair of compressor pairs having a second outlet port without communicating with the equalization port, wherein the first outlet port and the second outlet port correspond to the first outlet port. And optionally dimensioned to provide a lower volumetric index ratio (V _i ) than the second outlet port.